1. Field of the Invention
The present invention relates to a calendar mechanism and an analog timepiece equipped therewith, and more particularly relates to a calendar mechanism of a so-called big date form wherein the ones column and tens column of the date are indicated with separate date indicators, as a result of which it is possible to indicate the date in large characters, and to an analog timepiece equipped with the calendar mechanism.
2. Description of the Related Art
As a calendar mechanism of a big date form, a calendar mechanism is proposed which includes a first date indicator including a first date character indication portion which, being circular as a whole, indicates the ones column of the date, a circular first date indicator gear portion which, being formed on the inner periphery of the first date character indication portion, receives a torque, and a drive cam portion which, being formed on the back side of a first date character indication surface portion, defines an endless ring-shaped cam face; a drive cam lever including a driven lever portion whose one end portion abuts against the drive cam portion as a cam follower, and an operating lever portion which, being integral with the driven lever portion, includes a first fan-shaped gear portion at the leading end portion, wherein the one end portion of the driven lever portion is spring loaded in such a way as to be biased toward the cam face of the drive cam portion, and when the driven lever portion is pivoted in a condition in which the one end portion is in abutment with the cam face of the drive cam portion, the first fan-shaped gear portion of the operating lever portion is pivoted in accordance with the pivoting of the driven lever portion; and a second date indicator including a second date character indication portion which indicates the tens column of the date, and a second fan-shaped gear portion meshing with the first fan-shaped gear portion (for example, JP-A-2007-218856). With the calendar mechanism proposed in JP-A-2007-218856, the drive cam portion includes a first cam face portion corresponding to a case in which the tens column of the date is 0, in addition to a second and third cam face portion corresponding to a case in which the tens column of the date is 1 and 2, and a fourth cam face portion corresponding to a case in which the tens column of the date is 3.
Consequently, with this kind of heretofore known calendar mechanism, the drive cam lever is constantly subjected to a pivotal bias force in a direction in which the one end portion of the driven lever portion forming the cam follower is pressed against the cam face of the drive cam portion by a spring.
As a result of this, with the calendar mechanism proposed in JP-A-2007-218856, when the first date indicator is built in, it is necessary that the drive cam lever including the driven lever portion is shifted in order that the operating lever portion of the spring loaded drive cam lever does not abut against the drive cam portion of the first date indicator, and it is difficult to avoid taking a lot of trouble over the building in.